Yes you can mix colors. It is best to add just a little tint at a time to gain the desired change of color. Example if you add all the tint the change will be more semi-solid. Half the tint and it is semi-transparent in change. Less then that and you are just slightly changing the look.

RE: Super Seal Tint - I've been wanting to find a product like this for some time. Will the product still be transparent and just deepen the color of my paver bricks? Can the terra cotta and brick tints be combined to get a color somewhere inbetween?